Process of manufacturing thin sheets of nitro-cellulose



(No Model.) E. N. TODD.

PROCESS OFMANUFAGTURING THIN SHEETS OF NITRO GELLULOSE, &o. No. 428,654. I Patented May 27, 1890.

I WITNESSES: INVENTOR- d .E mundUl moolol UNITED STATES PATENT Oinn cn.

EDMUND N. TODD, OF NEWVARK, NEI/V JERSEY, ASSIGNOR TO THE CELLU- LOID VARNISH COMPANY, OF NEW JERSEY.

PROCESS OF MANUFACTURING THIN SHEETS OF NlTRO-CELLULOSE, &c.

SPECIFICATION forming part of Letters Patent No. 428,654, dated May 27, 1890.

Application filed July 8, 1889. Serial No. 316,813. (No model.)

To all whom it may concern.-

Be it known that I, EDMUND N. TODD, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in the Process of Manufacturin g Thin Sheets of Nitro-Oellulose, Pyroxyline, &c.; and I do hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawing, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in the manufacture of thin, transparent, and flexible sheets of nitro-cellulose and other compounds of pyroxyline; and my invention consists in a novel process, to be hereinafter more fully described, and finally embodied in the clauses of the claim, whereby the manufacture of such sheets of nitro-cellulose or pyroxyline is facilitated. As heretofore made by the old processes, these sheets were imperfect, not being of theuniform thickness which is so essential, or, perhaps,being imperfect on account of air-bubbles, which are very often caused to adhere to the wet coating of the material on the plates in the processes here tofore employed in the manufacture of such sheets, thereby causing the latter to be of little value, and hence a great loss to the manufacturer.

In carrying out my invention, I dissolve soluble pyroxylinc or nitro-cellulose in the various of the well-known solvents mixed with the various well-known menstrua, thus making a thick collodion, varnish, or solution of pyroXyline or nitro-cellulose, and sometimes a solution of nitrocellulose and camphor.

I prefer to use as a compound solvent acetate of methyl, acetate of amyl, fusel-oil, and oil of camphor, in which I dissolve the pyroxyline or nitro-cellulose. I desire to use the several ingredients in the following proportions, the same being in the proportion of one-half pound of nitro-cellulose or pyroxyline to one gallon of the mixture of acetate of methyl, acetate of amyl, fusel-oil, and oil of camphor, the several ingredients being in the proper proportions. If desirable, camphor may be added in the proportion of two ounces of camphor to one gallon of the solvent. I do not wish to be understood as limiting myself to the exact proportions here stated, for I may change this compound solvent or any of its ingredients; or, if desirable, under certain circumstances Imay use other solvents, and the above-mentioned compound solvent may be employed in various proportions of its ingredients. Having thus prepared this collodion or varnish, the process of manufacturing the thin and transparent sheets of nitro-cellulose or pyroxyline for photographic or other purposes is accomplished by the use of the apparatus described in the accompanying drawing, in which the figure shown is a vertical section of the device employed.

In said drawing, a is a tank or receptacle, provided at the top thereof with a removable cover I) and in the inclined bottom with a spigot or valve 0. Within this receptacle, preferably near the top thereof, is arranged one or more bars or rods (Z, upon which are hung or suspended plates of glass or other material e-by means of hooks f; or said plates maybe secured in said receptacle in any other convenient manner. These plates having been arranged in the receptacle a, the solution mentioned in the foregoing description hereto is then gently poured into said receptacle until the plates of glass are almost entirely immersed in the solution of collodion or varnish, and the same is then allowed to remain at rest for a short time until all the air has escaped and all air-bubbles have disappeared and the liquid solution remains quiet. As soon as the liquid within the tank has become quiet and all signs of air-bubbles on the surface thereof or on the plates have disappeared, the cover Z) is placed upon the receptacle a and the liquid allowed to remain quiet.

It is very essential that the plates 6 be suspended at their upper ends from the rods (Z, as thereby when the solution is poured into the receptacle the air-bubbles will rise to the top of the liquid, and there is no danger of any air adhering to the sides of the plates, as 100 areas is the case in apparatus where the plates are arranged in horizontal positions when the air has not been previously exhausted from the receptacle by means of an air-pump. Furthermore, when the liquid is being slowly drawn off through the spigot in the bottom, the same will be gradually lowered and will slowly pass down the sides of the plates, thereby resulting in a very thin and even coating adhering to said plates, which can easily be removed when dry in thin and transparent sheets of nitro-cellulose of uniform thickness.

The cover I) is provided with an outlet or pipe g, passing to the root of the building, through which pipe all disagreeable odors and gases or fumes escape without endan gcrin g the health of the operator.

\Vhen the liquid collodion or varnish has remained within the tank the required time to thoroughly form an even coating over the suspended plate, the spigot or valve in the bottom is opened and the liquid is allowed to flow slowly into a receptacle h, placed beneath the spigot, where the solution is stored until again required during the next process of coating the plates.

l5y means of the spigot or valve 0, I can regulate the flow of the liquid from the tank a, causing the same to escape gradually therefrom until said tank is entirely emptied. The great advantage thus attained is, that by regulating the flow of the liquid collodion from the receptacle or tank a, I accomplish, as a new result, the production. of a thin and even coating 011 the plates of glass or other material, which coats are free from any blemishes or air-bubblcs-such as are produced in the old method of dipping the glass plates in the solution or in the process of flowing the solution on the plates and rcnioving the same for drying. While the solution is very slowly and gradually being withdrawn from the bottom of the tank or receptacle and the level of the solution is becoming lower and lower, the solvents in that small part of the solution adhering to the plates evaporate, thereby leaving a very thin film of intro-cellulose adhering to the surfaces of the plates, which as it becomes exposed dries quickly and evenly, as is evident. lVhen all of the liquid has been drawn oil from the receptaelc, the coated plates of nitro-eellulose or pyroxyline are allowed to remain within the receptacle u until the coating thereon is thoroughly dried, free from dust, thereby resulting in the production of an even and perfect film of nitro-cellulosc or pyroxyline on said plates.

Another great advantage is attained in that when the plates are removed from the tank the material thereon is perfectly dry, and dust will not adhere to the material and be come impregnated with the same, as is the case with plates taken from the solution and put up to dry in another apartment, as is done in the old process.

As has already been stated in the above, the solution is drawn oil by the spigot or valve in the bottom of the receptacle into a closed vessel placed. beneath the same and stored therein for further use.

After having drawn ot't' the solution and when the coating on the plates has become perfectly dried, said plates are taken from the receptacle and the films of nitro-cellulosc or pyroxyline adhering to the plates are stripped therefrom, and the latter again returned to the tank, ready for the next process.

The films of nitro-cellulose removed from both sides of the plates of glass or other material are thin and of uniform thickness and are cut up into various sizes of sheets, ready for sale to the consumer.

It will be understood that I do not wish to limit myself strictly to the use of the apparatus shown in the drawing, for although the same may be of a desirable construction my process may readily be carried out in like manner by employing apparatus of different construction without departing from the scope of my invention.

It desirable, the solution may first be poured into the receptacle (1, and the plates of glass or other material may then be immersed in said solution, as will. be understood.

llavingthus described my invention, whatl claim is 1. The process of manufacturing thin transparent sheets of nitro-cellulose or pyroxyline, which consists in pouring a solution of collodion or pyroxyline or nitrocellulose into a receptacle having arranged therein verticallysuspended plates of glass or other analogous material, allowing said solution to remain quiet for a time in said tank, drawing off the said solution very slowly from the bottom of the tank, and thereby causing a thin film of solution to adhere to the plates directly above the level of the gradually-receding solution, the solvents in said adhering film evaporating and causing the film to dry evenly and quickly and to form upon said plate as the solution isbcing withdrawn from the tank an evenly-distributed iilm forming a thin and transparent sheet, as set forth.

2. The process of manufacturing thin transparent sheets of nitro-cellulosc or pyroxyline, which consists in placing in a closed receptacle or tank vertically-arrangod plates of glass or other material, pouring into said rcceptacle a solution of nitro-cellulose, pyroxyline, or collodion, placing a cover on said receptaele, allowing the solution therein to remain at rest and the escape of the air and fumes through an outlet in said cover, then very slowly drawing oil the said solution from the bottom, and thereby causing a thin iilm to adhere to the plates directly above the level of the gradually-receding solution, In testimony that I claim the invention set the solvents in said adhering film evaporatforth above I have hereunto set myhandthis 10 ing 111d causing the said film to easily and 6th day of July, 1889. quic y dry, and whereby as the solution is 5 being Withdrawn an evenly-distributed film EDMUND TODD' is produced, forming a thin and transparent Witnesses: sheet on the surfaces of the vertically-ar- FREDK. O. FRAENTZEL, ranged plates, as set forth. FREDK. S. RICE. 

